Bug 27946: Make Koha::ArticleRequest->request add a fee if required

Bug 27946: Make Koha::ArticleRequest->request add a fee if required

This patch makes the ->request method add a fee for the patron if
required. It relies on methods defined in Koha::Patron for the task. The
debit line is linked to the AR if applies.

To test:
1. Apply this patch
2. Run:
   $ kshell
  k$ prove t/db_dependent/Koha/ArticleRequest.t
=> SUCCESS: Tests pass!
3. Sign off :-D

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>